The subject matter relates generally to printed circuits having multiple conductive pathways for multiple signal lines.
Electrical connectors may be used within communication systems, such as telecommunication equipment, servers, data storage, transport devices, and the like. Some communication systems include interconnection systems that have a backplane or midplane circuit board and a plurality of daughter card assemblies that are configured to be mounted to the circuit board. For simplicity, the following only refers to a backplane circuit board, but it should be understood that a midplane circuit board may be used in a similar manner. Each of the daughter card assemblies includes a receptacle connector that is secured to a daughter card. The backplane circuit board has a plurality of header connectors that are mounted thereto. Each of the receptacle connectors is configured to mate with a respective header connector thereby communicatively coupling the corresponding daughter card assembly to the backplane circuit board. The backplane circuit board includes conductive vias and traces that interconnect different daughter card assemblies. Accordingly, different daughter card assemblies may be communicatively coupled to one another through the backplane circuit board.
The electrical components of these interconnection systems are typically configured for differential signaling. For example, the conductive vias of the backplane circuit board are electrically coupled to one another through the conductive traces. The conductive vias and the conductive traces are typically patterned to form pairs (referred to as “differential pairs”). The conductive traces for each differential pair have similar paths in order to reduce skew. In conventional differential signaling, two complementary signals are transmitted through the two conductive pathways of the differential pair. Data may be determined from a voltage difference between the two conductive pathways or current strength and direction in the two conductive pathways.
Although differential signaling systems are effective in communicating data, it has become more difficult to increase the bandwidth of these systems. More recently, a new signaling technique has been developed. The signaling technique is hereinafter referred to as “quad signaling” and is described in greater detail in U.S. Publ. No. 2011/0268225. Unlike differential signaling, which uses only two conductive pathways per signal line, the new signaling technique may use, for example, four conductive pathways for three signal lines. Thus, quad signaling may provide three signal lines while differential signaling may only provide two signal lines using the same number of conductive pathways. Although quad signaling may be implemented on the same electrical components used for differential signaling applications, the footprints of the conductive pathways may be improved so that quad signaling has more practical and commercial value.
Accordingly, there is a need for electrical components, such as printed circuits and circuit board assemblies, having footprints that are configured for quad signaling.